As-Saffah

as-Saffah (721-10 June 754) was the first caliph of the Abbasid Caliphate (from 750 to 754), succeeding Marwan II of the Umayyad Caliphate and preceding al-Mansur.

Biography
as-Saffah was the son of Muhammad ibn Ali, and he was from a branch of the Banu Hashim clan of the Quraysh tribe that descended from Abbas ibn Shaiba, an uncle of Muhammad. as-Saffah led a rebellion with his clan against the falling Umayyad Caliphate in the last days of the empire, rebelling in Khorasan. Supported by Shi'ite Muslims and the people of Khorasan, he overthrew the Umayyads from 743 to 750, although the Umayyads retained power in Spain with the Emirate of Cordoba and later the Cordoba Caliphate. Jews, Nestorian Christians, and Persians were well represented in his government, and he reigned for four years as Caliph of the new Abbasid Caliphate. He died of smallpox in 754.